The present invention relates generally to devices or modules that are incorporated into larger systems and rely on power from another system component's power supply. The invention relates more specifically to techniques for providing power to such devices or modules. Most of the discussion will concentrate on the example of hard disk drives (HDDs) that rely on power from a host.
While HDDs are constantly improving in terms of capacity, performance, and price, they still represent a significant portion of the system cost, and therefore it may be desired to re-use a HDD in a system that is different from that in which the HDD was previously deployed. For example, while a computer system may have become unusable for one or another reasons, the system's HDD may find utility in a spare drive bay in a different desktop system or in an enclosure for use as an external drive.
Unfortunately, as HDD technology has evolved, different form factors have come on the scene, and a HDD removed from one system may not easily fit in another. If the HDD is too large for the desired destination drive bay, the only resort is to put the HDD in an external enclosure. However there have been solutions for the case where the HDD is too small. For example, one existing solution uses a drive carrier to adapt a small form factor to a larger drive bay.
An additional problem may arise if the voltage or voltages provided by the new host differ from those required for the HDD. For example, a mobile drive will often be designed to operate only from a single, external 5-volt supply. A small form factor server drive, however, may use 5 volts for circuitry and 12 volts for motor control, or a single, external 12-volt supply in some emerging applications. This problem has been addressed by power supply adapters that provide one or more DC-to-DC converters or voltage regulators to step voltages up or down.
At this point, the re-use of the HDD may have become uneconomical, since the cost of a separate enclosure or a drive carrier and voltage adapter may exceed the cost of a comparable or better new HDD with the appropriate form factor and voltage requirements. The destination for the old HDD now becomes the county landfill.